The intervertebral discs are ligaments that connect the vertebrae of the spine together. They provide structural support for the spine and distribute forces exerted on the spinal column. An intervertebral disc consists of three major components: cartilage endplates, nucleus pulposus, and annulus fibrosus. The central portion, nucleus pulposus, is relatively soft and gelatinous, having a consistency similar to that of crabmeat. Surrounding the nucleus is the annulus fibrosus, which has a more rigid consistency and is largely comprised of concentric layers of fibrous tissue. The annular portion serves to provide peripheral mechanical support to the disc, afford torsional resistance, and contain the softer nuclear portion and resist its hydrostatic pressure.
Unfortunately, intervertebral discs are susceptible to injury. Disc herniation occurs when the nucleus begins to extrude through an opening in the annulus, often to the extent that the herniated material impinges on nerve roots in the spine, resulting in pain. One way to address such pain is remove the bulging disk material surgically through a nucleotomy and/or anulotomy, thus relieving pressure on the nerve roots. Further treatment might include the use of intervertebral spacers to reduce the pressure exerted on the disc by the spine. However, very few products are currently available that address the repair of the annulus fibrosus per se. This is true whether the annular tissue has been damaged by herniation, or by the creation of surgical access ports in the course of disc repair.
There exists a need for methods and instruments for repair of the annulus fibrosus. Any such methods that are simple and compatible with minimally-invasive surgical techniques would be particularly desirable.